1. Field of the Invention
The present invention relates to communication apparatuses, and particularly to a communication apparatus equipped with two antennas used for two different communication systems.
2. Description of the Related Art
Typical communication apparatuses include mobile terminals, such as personal digital assistants (PDAs), and notebook personal computers (hereinafter sometimes referred to as “PCs”). Many PCs have Bluetooth®, which is used for wirelessly connecting mice or keyboards, or wireless local area networks (LANs), which are used for wirelessly connecting PCs to printers or other PCs. For Bluetooth® or IEEE802.11b wireless LAN communication, which is currently the most commonly used, the 2.4 GHz telephone band is used. For higher-data rate IEEE802.11g, which will come into widespread use in the near future, the 2.4 GHz band is also used. Accordingly, if Bluetooth® and a wireless LAN are used at the same time, radio interference may occur, and countermeasures against such interference must be taken.
To solve this problem, an artificial magnetic conductor (AMC) has been developed by Etenna Corporation in the United States. The AMC is formed by modifying a known magnetic conductor to shield it from surface waves.
However, the AMC is cumbersome, heavy, and expensive since it is formed by modifying a known magnetic conductor.